Numerous apparatuses have been proposed for automatic refueling of vehicles, but none have been commercially applied to retail gasoline outlets because of the expense and complexity of the systems. To be economically competitive with customers ability to refuel automobiles manually, or an attendant, such an automated refueling system must be relatively simple, and must be assembled from relatively inexpensive components. Additionally, it is necessary that modifications to the vehicle to be refueled be minimal. Also, the refueling nozzle area must be designed to be in an area that is free from the possibility of electrical sparks.
U.S. Pat. No. 3,527,268 suggests an automated refueling system that includes a movable head having three functional arms, an arm to open a fuel cap cover lid, an arm to remove a fuel cap, and a fuel fill nozzle that is inserted into the fuel inlet. There are therefore five physical steps used: fuel cap lid opening; cap removal; fuel fill step; cap replacement; and cap lid closure. The apparatus of '268 must be repositioned after each of these five operations. This repositioning adds to the complexity of any control scheme, adds to the time required to complete the operation, and results in an operation that would be perceived by the customer as unduly complex. Additionally, '268 initiates fuel flow upon the fuel tube being extended until a limit switch indicates it is fully extended. The initial positioning of the end effector must therefore be extremely accurate with relationship to the fuel inlet nozzle to provide any sort of seal on the fuel inlet. This precise of positioning with relationship to the fuel inlet nozzle is not possible because of variations in dimensions of fuel tank inlet tubes, variations in the installation of fuel tanks in vehicles, and variations in installation of fenders on the vehicles. Even if the position of the fuel inlet is determined by the position of the fuel cap, the angle of the fuel inlet orifice to vertical may vary sufficiently to prevent a seal being achieved at a predetermined fuel fill tube extension.
The apparatus of patent '268 reposition the end-effector for the different operations by rotation of the head of the end-effector. The connections and control conduits must therefore all be rotatable, and many require rotatable seals. This adds considerable cost and complexity to the apparatus of '268.
EPO Patent Publication No. 0 418 744 A2 suggests a robot that is mounted on a track adjacent to a stall in which a vehicle to be refueled is to be parked. In the apparatus of Publication '744, the robot picks up a selected refueling nozzle and inserts the nozzle into a specially provided insert in the vehicle's fuel inlet. Besides for the specially provided insert for the fuel inlet, the vehicle needed to be modified to provide the driver the capability of opening and closing the fuel inlet cover lid from the inside of the vehicle.
Patent PCT/IT/00017 suggests an automated refueling apparatus much like that of patent '268, but with a line of center of rotation turned 90.degree. from the line of center of rotation of the fuel dispensing head. PCT/IT/00017 also suggests positions of the filling cover door and the fuel plug indicated by cameras searching for reflectors and fluorescent paint. Fuel flow is initiated when a sensor touches the fuel inlet, indicating that the fuel nozzle is inserted into the inlet. This mechanism would not necessarily indicate that a sealing contact is made.
It is therefore an object of the present invention to provide an apparatus for automated refueling of vehicles that is relatively simple and inexpensive. It is a further object to provide such a system wherein the electrical switches and sensors in the area around the refueling nozzle are minimized.